Convertible timing device

ABSTRACT

A timing device is affixed to an actuator which is a part of a relay or a similar apparatus and which is moved between a first position and a second position. The timing device provides a timed interval between movement of the actuator and some later desired event. The timed interval may be measured from the departure of the actuator from either the first position or the second position, as selected by affixing the actuator to either one end or the other end of an actuator coupling means which couples the actuator to the timing means of the timing device.

United States Patent Flanagan 1 CONVERTIBLE TIMING DEVICE [72] Inventor: Robert M. Flanagan, Summit, NJ.

[73] Assignee: Amerace Esna Corporation, New

York, NY.

[22] Filed: Aug. 30, 1971 [21] Appl. No.: 175,970

52 us. Cl ..335/61 51 161. ci. ..H0lh 7/03 5s Field 61 Search ..335/61, 59, 60, 62, 63, 64

[56] References Cited UNITED STATES PATENTS 2,855,481 10/1958 Lindahl ..335/61 3,509,501 4/1970 Brovedan ..335/61 1451 Aug. 15, 1972 3,599,131 8/1971 Flanagan 335/6l Primary Examiner-Harold Broome Att0rneySamuelson & Jacob [5 7 ABSTRACT A timing device is affixed to an actuator which is a part of a relay or a similar apparatus and which is moved between a first position and a second position. The timing device provides a timed interval between movement of the actuator and some later desired event. The timed interval may be measured from the departure of the actuator from either the first position or the second position, as selected by afiixing the actuator to either one end or the other end of an actuator coupling means which couples the actuator to the timing means of the timing device.

8 Claims, 5 Drawing Figures PATENTEUMIG 1 I9 2 3'. 684.985

SHEEI 1 OF 2 T5131? 1a 62 as 36 46 50 54 48 "till n" 60 62 INVENTOR. ROBERT M FLHNAGQN FITTO R NEHS PATENTEDws 15 I972 SHEEI 2 OF 2 INVENTOR. ROBERT M FLFINRGRN CONVERTIBLE TIMING DEVICE The present invention relates generally to timing devices and pertains, more specifically, to time-delay devices of the type in which some desired event, such as the opening or closing of an electric circuit, is accomplished after the lapse of a predetermined time interval following the actuation of the device by a relay or some like apparatus.

A variety of time-delay control apparatus is currently available in which a timing device is operated by an actuator to provide a timed interval between actuation of the timing device and the occurrence of some desired event, such as the operation of an electric switch. Among the most widely accepted of such control apparatus are those which employ a pneumatic timing device together with a solenoid actuator so that the timed interval can be measured either from activation or deactivation of the solenoid.

One such apparatus is found in US. Pat. No. 2,489,381 issued on Nov. 29, 1949, to Lindahl wherein there are disclosed two embodiments of the apparatus, one in which a timed interval is measured between deactivation of a solenoid and actuation of an electric switch and the other in which a timed interval is measured between activation of a solenoid and actuation of an electric switch. In both embodiments, or types, the apparatus includes not only a pneumatic timing device and an electric switch, but a solenoid as well.

In many instances it has been found desirable to provide a timed interval between the movement of the actuator of a relay, or a like apparatus, and the occurrence of a desired event, such as the actuation of an electric switch. Because the relay, or the like apparatus, is already provided with an actuator which moves between two positions,- it would be advantageous to make use of the movement of that actuator to operate a timing device. An additional advantage would be obtained if a single timing device could be employed to provide both of the above types of time delay; that is, the timing device would selectively measure the desired time interval from movement of the actuator from either one of the two positions toward the other of the two positions.

It is therefor an important object of the invention to provide a timing device which can be coupled to the actuator of an existing relay or a like device for providing a timed interval between actuation of the relay and the occurrence of a desired event and in which the timed interval can be measured selectively from movement of the actuator from either one of two positions toward the other of the two positions.

Another object of the invention is to provide a timing device of the type described wherein the selection of the position of the actuator from which the timed interval will be measured is determined by the manner in which the device is coupled to the actuator.

Still another object of the invention is to provide a timing device which is easily attached to an existing relay, or a like apparatus, to provide the desired timed interval after actuation of the relay.

A further object of the invention is to provide a timing device of the type described which utilizes a timing mechanism of the type which is reliable and has been accepted commercially.

A still further object of the invention is to provide a timing device of the type described which provides a high degree of flexibility of use while being relatively inexpensive to manufacture.

The above objects, as well as still further objects and advantages are attained by the invention which may be described briefly as a convertible timing device for use in connection with a relay, or a like apparatus, having an actuator which is moved between a first position and a second position, the timing device providing a timed interval measured selectively from the departure of the actuator from either one of the positions thereof to a desired event, the timing device comprising a frame, a motion transmitting member mounted in the frame for movement along a prescribed path of travel in either one of two directions between a first location and a second location, timing means on the frame and coupled with the motion transmitting member so as to permit movement of the motion transmitting member from the first location to the second location thereof and for effecting. movement of the motion transmitting member at a predetermined rate in one only of the two directions to establish the timed interval between the departure of the motion transmitting member from the second location thereof and the arrival of the motion transmitting member at the first location thereof, means responsive to the arrival of the motion transmitting member at the first location thereof for detecting the arrival, thereby effecting the desired event, and actuator coupling means mounted on the frame for movement between first and second positions and including a first portion for engaging the motion transmitting member to move the motion transmitting member to the second location thereof as the actuator coupling means moves from the first position to the second position thereof and to retain the motion transmitting member at the second location thereof as long as the actuator coupling means is in the second position thereof, and for disengaging from the motion transmitting member upon movement of the actuator coupling means from the second position to the first position thereof to free the motion transmitting member for movement toward the first location thereof in response to operation of the timing means, and a second portion for enabling selective attachment of the actuator coupling means to the actuator such that the actuator is in either one of the first and second positions thereof when the actuator coupling means is in one of the first and second positions thereof and movement of the actuator from the one position to the other position thereof will move the actuator coupling means from the one position to the other position thereof.

The invention will be more fully understood, while still further objects and advantages will become apparent, in the following detailed description of a preferred embodiment of the invention illustrated in the accompanying drawing, in which:

FIG. l is an elevational view of a timing device constructed in accordance with the invention and attached to a relay;

FIG. 2 is an enlarged longitudinal cross-sectional view of the timing device and relay of FIG. 1;

FIG. 3 is a fragmentary cross-sectional view similar to FIG. 2 with the component parts in another operating position;

FIG. 4 is a fragmentary cross-sectional view similar to FIG. 3 but with the component parts in still another operating position; and

FIG. 5 is an enlarged fragmentary cross-sectional view taken along line 5-5 of FIG. 1.

Referring now to the drawing, and especially to FIG. 1 thereof, a timing device constructed in accordance with the invention is illustrated generally at and is shown attached to a relay 12. The timing device 10 has a frame 14 which extends longitudinally between a first end 16 and a second end 18. The first end 16 of the frame 14 includes a support surface 20 which is seen to be resting upon a corresponding support surface 22 of the housing 24 of the relay 12. Attachment means, shown in the form of a dovetail connection 26 including a tongue 28 on the frame 14 and a corresponding groove 30 on the housing 24 secure the frame 14 to the housing 24 and the timing device 10 to the relay 12. A corresponding dovetail tongue 32 is located at the opposite end 18 of the frame 14 and is received within a dovetail groove 34 in a cover plate 36.

Turning now to FIG. 2, the relay 12 is designed to open and close an electric circuit between a first conductor affixed to a first terminal member 42 and a second conductor 44 affixed to a second terminal member 46. Each terminal member 42 and 46 is electrically connected to a corresponding contact 48. A contact bar 50 is carried by a contact block 52 of insulating material and includes a pair of electrical contacts 54 corresponding to the electrical contacts 48 of the terminal members 42 and 46. The contact block 52 is affixed to an armature 56 mounted for sliding movement in a vertical direction, as viewed in FIG. 2, within the relay housing 24 and is biased vertically upwardly by a helical spring 58. The armature 56 includes depending portions 60 which extend into the field of an electrically conductive coil 62 embedded in the housing 24 of the relay 12. A core 64 is fixed within the housing 24 and includes portions 66 extending up wardly into the field of the coil 62 such that upon energization of the coil, the armature 56 is drawn downwardly toward the core 64 thereby pulling the contact block 52 downwardly and engaging the corresponding contacts 48 and 54 to complete an electrical circuit between the terminal members 42 and 46. Upon deenergization of the coil 62, the helical spring 58 will return the armature 56 to the position shown in FIG. 2, thereby opening the electrical circuit between the terminal members 42 and 26 and the conductors 40 and 44.

The timing device 10 may be attached to the relay 12 for the purpose of providing a timed interval measured either from the making or the breaking of the electrical circuit between terminal members 42 and 46 of the relay 12. At the end of the timed interval, a desired event will take place; in this instance, the desired event is effected by the actuation of an electrical switch 68 in the timing device 10, as will be described in greater detail hereinafter. When the timing device 10 is afiixed to the relay 12 in the manner illustrated in FIG. 2, the timed interval will be measured from the opening of the electrical circuit between the terminal members 42 and 46.

The relay 12 carries an actuator shown in the form of a rod 70 threaded into the contact block 52 for move ment therewith between a first position, as shown in FIG. 2, and a second position, illustrated in FIG. 3. The actuator rod 70 is coupled to the timing device 10 through an actuator coupling means shown in the form of longitudinally extending slide member 72 mounted upon the frame 14 for sliding movement in a longitudinal direction along a pair of posts 74 affixed to the frame and extending through corresponding apertures 76 in lower and upper arms 80 and 82, respectively, which comprise a portion of the actuator coupling means and extend laterally from the opposite ends 84 and 86, respectively, of the slide member 72. Each of the lower and upper arms 80 and 82 have a lateral slot 88 with a T-shaped cross-section and the actuator rod 70 carries an integral head 90 which can be received in either of the T-shaped slots 88 and is shown engaged within the T-shaped slot of the lower arm 80 such that upon downward movement of the actuator rod 70 from the first position to the second position the slide member 72 will be moved from a first position, as shown in FIG. 2, to a second position illustrated in FIG. 3.

As the slide member 72 moves downwardly from the first position to the second position thereof, another portion of the actuator coupling means, illustrated in the form of a finger 92, which is integral with the slide member 72 and extends laterally therefrom intermediate the ends 84 and 86 thereof, also moves downwardly and engages a lateral shoulder 94 on a motion transmitting member 96 to drive the motion transmitting member 96 downwardly along a longitudinal path of travel from a first location, as shown in FIG. 2, to a second location, illustrated in FIG. 3. Such downward movement of the motion transmitting member 96 moves a contact plunger 98 downwardly, by virtue of the engagement of the motion transmitting member 96 with a flange 100 integral with the contact plunger 98, resulting in the downward displacement of contact arms 102 of the electrical switch 68 and the concomitant throwing of moveable contacts 104 carried by the contact arms 102 from lower fixed contacts 106 to upper fixed contacts 108 by an over-center spring mechanism 110 of the electrical switch 68. Th us, upon actuation of the relay 12 to make an electrical circuit between terminal members 42 and 46, the electrical switch 68 of the timing device 10 is actuated to make an electrical circuit between the upper fixed contacts 108. Each of the contacts 106 and 108 are electrically connected to external terminals (not shown) which enable the switch 68 to be connected to an external electrical device (not shown) so that switch 68 can perform a control function.

The upper portion 112 of the motion transmitting member forms a part of a pneumatic timing mechanism 114 of a type now known in the art. A very similar pneumatic timing mechanism is described in US. Pat.

No. 3,599,l3l issued on Aug. 10, 1971, to Flanagan et al. The pneumatic timing mechanism 114 includes an air chamber 116 divided into an upper chamber portion 118 and a lower chamber portion 120 by a flexible diaphragm 122 secured around its outer periphery to the frame 14 and affixed adjacent its inner periphery to a metallic skirt 124 having a central aperture 126 surrounded by an integral sleeve 128 and a plurality of ports 130 passing through the skirt 124 at the base of the sleeve 128. The motion transmitting member 96 projects upwardly through the sleeve 128 and is coupled to the skin 124 by means of a helical spring 132 extending between the skirt and a retainer 134 held in place upon the motion transmitting member 96 by a screw 136. The helical spring 132 biases the skirt 124 downwardly and urges a resilient annular member 138, which is affixed to the skirt, against a seat provided by an upper surface 140 of the motion transmitting member 96. When the motion transmitting member 96 is urged downwardly by the rapid downward movement of the slide member 72 and the finger 92, the helical spring 132 is compressed and the upper suiface 140 of the motion transmitting member 96 pulls away from the resilient annular member 138 to open a passage for air to pass from the lower chamber portion 120 to the upper chamber portion 118 through the ports 130 in the skirt 124, as illustrated by the arrows in FIG. 3. Thus, rapid downward movement of the motion transmitting member is not impeded by the air in the chamber 116 and the motion transmitting member will be moved downwardly, thereby compressing a helical timing spring 142 which extends between the motion transmitting member 96 and the frame 14.

As long as the coil 62 of the relay 12 is energized and the actuator rod 70 remains in the second position thereof, the slide member 72 will also remain in its second position and the motion transmitting member will be retained in its second location by the engagement of finger 92 with the shoulder 94 on the motion transmitting member 96. Upon deenergization of the coil 62 of the relay 12, the actuator rod 70 will depart from its second position and return to the first position, as shown in FIG. 4, returning the slide member 72 to its first position and thereby moving the finger 92 upwardly to disengage the finger from the shoulder 94 of the motion transmitting member 96. The motion transmitting member 96 then becomes free to move in an opposite direction, or upwardly, in response to the biasing force of the timing spring 142. However, upward movement of the motion transmitting member 96 enables the helical spring 132 to seat the annular member 138 upon the upper surface 140 of the motion transmitting member thereby closing the ports 130 to the passage of air from the upper chamber portion 118 to the lower chamber portion 120.

Referring now to FIG. 5, as well as to FIG. 4, upward movement of the motion transmitting member 96 is permitted by the passage of air from the upper chamber portion 1 18 to the lower chamber portion 120 through a timing valve means 144 which is selectively adjustable to regulate the flow of air from the upper chamber portion to the lower chamber portion so as to regulate the rate of travel of the motion transmitting member as the motion transmitting member moves upwardly. The timing valve means 144 is very similar to that described in the aforementioned US. Pat. No. 3,599,131, although other available timing valve means may be employed. Air from the upper chamber portion 118 enters a passage 146 which communicates with a recess 148 in the frame 14 of the timing device 10. Air in the recess 148 is passed through a disc 150 of porous metal into a channel 152 of a shutter member 154 and is shunted from the channel 152 through a notch 156 and into an annular groove 158 in the frame 14. The annular groove 158 communicates with a further passage 160 leading to lower chamber portion 120. Thus, air from the upper chamber portion 118 is throttled by the disc 150 of porous metal and its further metered by the channel 152 in the shutter member 154 to regulate the rate of movement of the motion transmitting member 96 and thereby establish a timed interval during which the motion transmitting member travels from its first location to its second location. The shutter member 154 is affixed to a dial 162 which is mounted for rotation upon the frame 14 by a screw 164 (see FIG. I) and the dial may be rotated to select a desired duration for the timed interval, as indicated by a pointer 166 and a scale 168, in the manner described more fully in the aforementioned US. Pat. No. 3,599,131.

As best seen in FIG. 4, the motion transmitting member 96 carries a collar 170 which is threaded onto the motion transmitting member at the lower end thereof. A helical spring 172 extends between the collar 170 and the flange 100 of the contact plunger 98 so that as the motion transmitting member 96 moves upwardly, the helical spring 172 is compressed, enabling some relative movement between the motion transmitting member and the contact plunger. Upon continued upward movement of the motion transmitting member 96 and the collar 170, the collar will engage the flange 100 of the contact plunger 98 and the contact plunger itself will move upwardly. Since movement of the motion transmitting member and the contact plunger upwardly is at a relatively slow rate, the deadcenter position of the over-center spring mechanism 110 of the electrical switch 68 is approached at a relatively slow rate. Thus, the contact pressure between the moveable conacts 104 and the fixed contacts 108 will gradually tend to be reduced. Since it is undesirable for the contact pressure to be reduced below a predetermined minimum amount, as that predetermined amount is approached the helical spring 172 will move the contact plunger 98 rapidly upwardly relative to the motion transmitting member 96 so that the over-center spring mechanism 110 will be thrown rapidly through its dead-center position and moveable contacts 104 will be snapped from the upper fixed contacts 108 to the lower fixed contacts 106. Thus, at the end of the timed interval, measured from the deactivation of the coil 62 of the relay 12, the opening of the electrical circuit between the terminal members 42 and 46 and the movement of the actuator rod from its second position toward its first position, the electric switch 68 is actuated to open the electrical circuit between fixed contacts 108 and to close an electrical circuit between fixed contacts 106.

When it is desired to provide a timed interval measured from the energization of the coil 62 of the relay 12, the closing of an electric circuit between terminal members 42 and 46 and the movement of the actuator rod 70 from the second position to the first position thereof, the timing device 10 may be detached from the housing 24 of the relay 12 by sliding the timing device 10 in a direction perpendicular to the plane of the paper (as viewed in FIG. 1) to release the dovetail connection 26 between the frame 14 and the housing 24 and to release the head 90 of the actuator rod 70 from the T-shaped slot 88 in the lower arm of the slide member 72. The cover plate 36 may then be removed from the opposite end 18 of the frame 14 in a like sliding manner and the entire timing device 10 may be inverted and once again attached to the housing 24 of the relay l2 utilizing the dovetail tongue 32 at the opposite end 18 of the frame and engaging the head 90 of the actuator rod 70 within the T-shaped slot 88 of the upper arm 82 of the slide member 72.

By thus inverting the timing device 10, it will be seen that upon deenergization of the coil 62 of the relay 12, the actuator rod 70 will move to its first position, but the slide member 72 will be moved to its second position and the motion transmitting member 96 will be moved to its first location. Upon energization of the coil 62 of the relay 12, the actuator rod 70 will be moved to its second position and will return the slide member 72 to its first position thereby releasing the motion transmitting member for movement, over a timed interval, from its first location to its second location. Thus, the timed interval will be measured from energization of the coil 62 of the relay 12 rather than from deenergization of the coil 62 of the relay.

Hence, the timing device is a convertible device in that it provides a timed interval which may be measured selectively from either the opening of the circuit between the terminal members 42 and 46 of the relay or the closing of the circuit between these terminal members.

The operation of the timing device 10 and the ability of the timing device to be released from the housing 24 of the relay l2, inverted and reattached to the housing of the relay is enhanced by alignment of the path of travel of the motion transmitting member 96 with the path of movement of the actuator rod 70 of the relay by virtue of the configuration of the slide member 72 with its laterally extending arms 80 and 82 and the laterally extending finger 92. In addition, the actual timing mechanism 114 is located entirely between the ends of the slide member 72 and the laterally extending arms 80 and 82. Such an arrangement provides a compact device which requires very little space in relation to the space required by the relay.

It is to be understood that the above detailed description of an embodiment of the invention is provided by way of example only. Various details of design and construction may be modified without departing from the true spirit and scope of the invention as set forth in the appended claims.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

l. A convertible timing device for use in connection with a relay or a like apparatus having an actuator which is moved between a first position and a second position, the timing device providing a timed interval measured selectively from the departure of said actuator from either one of said positions thereof to a desired event, said timing device comprising:

a frame;

a motion transmitting member mounted in the frame for movement along a prescribed path of travel in either one of two directions between a first location and a second location;

timing means on the frame and coupled with the motion transmitting member so as to permit movement of the motion transmitting member from the first location to the second location thereof and for effecting movement of the motion transmitting member at a predetermined rate in one only of said two directions to establish said timed interval between the departure of the motion transmitting member from the second location thereof and the arrival of the motion transmitting member at the first location;

means responsive to the arrival of the motion transmitting member at the first location thereof for detecting said arrival, thereby effecting said desired event; and

actuator coupling means mounted on the frame for movement between first and second positions and including a first portion for engaging the motion transmitting member to move the motion transmitting member to the second location thereof as the actuator coupling means moves from the first position to the second position thereof and to retain the motion transmitting member at the second location thereof as long as the actuator coupling means is in the second position thereof, and for disengaging from the motion transmitting member upon movement of the actuator coupling means from the second position to the first position thereof to free the motion transmitting member for movement toward the first location thereof in response to operation of the timing means, and a second portion for enabling selective attachment of the actuator coupling means to said actuator such that the actuator is in either one of the first and second positions thereof when the actuator coupling means is in one of the first and second positions thereof and movement of the actuator from said one position to the other position thereof will move the actuator coupling means from said one position to the other position thereof. 2. The convertible timing device of claim 1 wherein: the prescribed path of travel of the motion transmitting member lies along a straight line and the two directions are opposite longitudinal directions; and i the actuator coupling means includes a slide member extending longitudinally between opposite ends and mounted on the frame for sliding movement parallel to said opposite longitudinal directions.

3. The convertible timing device of claim 2 wherein:

the motion transmitting member includes a lateral shoulder; and

the first portion of the actuator coupling means includes a finger extending laterally from the slide member intermediate the ends thereof and fixed for movement with the slide member for engaging, retaining and disengaging the lateral shoulder of the motion transmitting member.

4. The convertible timing device of claim 3 wherein the second portion of the actuator coupling means includes a pair of arms extending laterally, one from each end of the slide member, each arm carrying affixing means for selectively receiving and affixing the actuator for movement with the slide member.

5. The convertible timing device of claim 4 wherein the frame includes opposite ends adjacent the opposite ends of the slide member, each end of the frame having a mounting surface for engaging a corresponding surface of said relay or like apparatus.

6. The convertible timing device of claim 5 wherein the timing means is located longitudinally between the 8. The convertible timing device of claim 7 wherein the means responsive to the arrival of the motion transmitting member at the first location thereof is an electric switch actuated by movement of the motion transmitting member toward and away from the first location thereof. 

1. A convertible timing device for use in connection with a relay or a like apparatus having an actuator which is moved between a first position and a second position, the timing device providing a timed interval measured selectively from the departure of said actuator from either one of said positions thereof to a desired event, said timing device compRising: a frame; a motion transmitting member mounted in the frame for movement along a prescribed path of travel in either one of two directions between a first location and a second location; timing means on the frame and coupled with the motion transmitting member so as to permit movement of the motion transmitting member from the first location to the second location thereof and for effecting movement of the motion transmitting member at a predetermined rate in one only of said two directions to establish said timed interval between the departure of the motion transmitting member from the second location thereof and the arrival of the motion transmitting member at the first location; means responsive to the arrival of the motion transmitting member at the first location thereof for detecting said arrival, thereby effecting said desired event; and actuator coupling means mounted on the frame for movement between first and second positions and including a first portion for engaging the motion transmitting member to move the motion transmitting member to the second location thereof as the actuator coupling means moves from the first position to the second position thereof and to retain the motion transmitting member at the second location thereof as long as the actuator coupling means is in the second position thereof, and for disengaging from the motion transmitting member upon movement of the actuator coupling means from the second position to the first position thereof to free the motion transmitting member for movement toward the first location thereof in response to operation of the timing means, and a second portion for enabling selective attachment of the actuator coupling means to said actuator such that the actuator is in either one of the first and second positions thereof when the actuator coupling means is in one of the first and second positions thereof and movement of the actuator from said one position to the other position thereof will move the actuator coupling means from said one position to the other position thereof.
 2. The convertible timing device of claim 1 wherein: the prescribed path of travel of the motion transmitting member lies along a straight line and the two directions are opposite longitudinal directions; and the actuator coupling means includes a slide member extending longitudinally between opposite ends and mounted on the frame for sliding movement parallel to said opposite longitudinal directions.
 3. The convertible timing device of claim 2 wherein: the motion transmitting member includes a lateral shoulder; and the first portion of the actuator coupling means includes a finger extending laterally from the slide member intermediate the ends thereof and fixed for movement with the slide member for engaging, retaining and disengaging the lateral shoulder of the motion transmitting member.
 4. The convertible timing device of claim 3 wherein the second portion of the actuator coupling means includes a pair of arms extending laterally, one from each end of the slide member, each arm carrying affixing means for selectively receiving and affixing the actuator for movement with the slide member.
 5. The convertible timing device of claim 4 wherein the frame includes opposite ends adjacent the opposite ends of the slide member, each end of the frame having a mounting surface for engaging a corresponding surface of said relay or like apparatus.
 6. The convertible timing device of claim 5 wherein the timing means is located longitudinally between the pair of arms of the slide member and the longitudinal direction of the path of travel of the motion transmitting member is aligned with the affixing means carried by said arms.
 7. The convertible timing device of claim 6 wherein the timing means is a pneumatic timing mechanism including means for selectively varying the duration of the timed interval.
 8. The convertible timing device of claim 7 wherein the means responsive to the arrivAl of the motion transmitting member at the first location thereof is an electric switch actuated by movement of the motion transmitting member toward and away from the first location thereof. 